Improvement in rock-drills



Patented Oct. 17,187]

Improvement in Rock Drills. I

AM, mo ra-unman/wum m in mam/v55- moansl J.'CHAPMAN. No. 120,036

UNITE TATES PATENT OFFICE.

JOHN CHAPMAN, OF AMSTERDAM, NEW YORK.

IMPROVEMENT IN ROCK-DRILLS.

To all whom it'may concern:

Be it known that I, J OHN CHAPMAN, of Amsterdam, in the county ofMontgomery and State of New York, have invented a new and usefulImprovenient in Rock-Drilling Machine; and I do hereby declare that thefollowing is a full, clear, and exact description thereof, which willenable others skilled in the art to make and use the same, referencebeinghad to the accompanying drawing forming part of this specification.

Figure 1 represents a vertical longitudinal section of my improvedrock-drill, taken on the line 0 c, Fig. 2. Fig. 2 is a verticaltransverse section of the same on the line K K, Fig.1. Fig. 3 is ahorizontal section of the same on the line 0 70, Fig. 1. Fig. 4 is alower end view of the drill-shaft.

Similar letters of reference indicate corresponding parts.

This invention relates to a new machine for revolving and striking theshank of a rock-drill with the object of obtaining an equal amount ofeffective power to a suitable depth. The invention consists in theimprovement of mechanism for elevating the shaft of a rock-drill, ashereinafter fully described and subsequently pointed out in the claim.

A in the drawing represents the frame of my improved rock-drill. B isthe upper portion of the drill-shaft, made prismatic, and fitted loosethrough a disk, at, and cog-wheel b. The latter receives rotary motionby another toothed wheel, 01, from the driving-shaft O, which has itsbearings in the frame A. By this shaft 0 the drill shaft is constantlyrotated. From the face of the disk at project ears 0, which supportpivoted pawls D D, as shown. These pawls have friction-rollers f f attheir outer ends, while their inner ends are pointed; Thefriction-rollers rest on a circular stationary track, 9, and revolvethereon around the axis of the shaft B, as the disk at is being revolvedby the same. Above the rollers ff is suspended from a plate, h, anotherring or track, 75, of aboutthe same diameter as the track g. In thetrack 1' are two pendent cams, j 7', and the track 9 carries twoprojeeting cams, l l, as shown. Whenever the rollers f are in contactwith the edges of the cams j the outer ends of the pawls D are depressedand their inner ends raised against shoulders m m of the drill-shaft.The latter is thereby slightly elevated, so as to clear the drill E fromthe rock, and then, as the rollers f are in contact with the cams I,dropped again upon the same, having been turned while thus elevated. Inthis manner the changes of position are efl'ected without undue frictionof machinery. When the rollers f are on the cams Z the inner ends of thepawls are lowered quite clear of the drill-shaft, as is clearly shown inFig. 1. Directly above the drillshaft are on the frame two verticalguides or posts, a a, between which a dropweight, F, is arranged. Thesame is provided with a projecting finger, 0, which is, at properintervals, brought in contact with the projecting pins 12 of a rotatingwheel, G, that is connected with the drivinggear. Thereby the weight Fis raised, and, as the pins 12 leave the finger 0, suddenly dropped uponthe drill-shaft, which it strikes with suflicient force to cause thedesired descent of the tool.

The strokes imparted to the drill-shaft by means of the weight F aresubsequent to every slight elevation of the same by pawls and ratherindependent of the same; that is to say, the drill-shaft is loosened bybeingv slightly raised and lowered, and is then struck by the drop.

The machine can be used to drill to a suitable depth by attachingsections to the lower end of the drill-shaft, as may be found necessary.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- The stationary cam-tracks g Z and :i j, combined,

"as described, with the pawl-rollers f, so that the latter will move onand between the former, as and for the purpose specified.

The above specification of my invention signed by me this 5th day ofJuly, 1871.

JOHN GHAPMAN. Witnesses:

GEO. W. MABEE,

T. B. Mosnm. 124

